MEMORANDUM

TO: Samantha Lewis, EPA/EAD 

Damon Highsmith, EPA/EAD 

FROM: Meghan Camp, ERG 

DATE: 14 January 2011

SUBJECT: SolmeteX Meeting Minutes for 15 December 2010 

On 15 December 2010, EPA met with Al Dube of SolmeteX to discuss amalgam 

separator technologies. Discussion topics included:

• Introductions; 

• Background on Amalgam Separators and SolmeteX Technology, including: 

 Separation Efficiency and ISO Standard; 

 Wastewater Flow Issues; 

 Installation, Operation, and Maintenance; and 

• Regulatory Considerations. 

Attachment 1 lists the meeting participants, and Attachment 2 contains a copy of a presentation 

that Mr. Dube handed out during the meeting. 

Introductions 

Mr. Dube provided background information on SolmeteX, which is the largest seller of 

amalgam separators in the U.S. SolmeteX introduced the amalgam separator in 2000 and 

currently accounts for 85 percent of the market. In addition, SolmeteX developed the logistics for 

transferring the waste amalgam collected by the separators from dental offices to disposal and 

recycling centers. 

Background on Amalgam Separators and SolmeteX Technology 

Prior to the meeting, EPA sent Mr. Dube a list of questions for discussion. The following 

summarizes information that Mr. Dube provided in response to these questions. 

Please describe the technology-basis of your separator models.

Amalgam separators are solids collectors that operate using the following separation 

techniques: filtration, sedimentation, or centrifuge. SolmeteX amalgam separators use a 

combination of sedimentation and filtration. Amalgam separators do not specifically target 
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14 January 2011 

Page 2 of 7 

mercury for removal, rather they collect all solid materials that are suctioned down the vacuum 

line. 

Does the water need to run all day through your separators or only run when vacuum is on?

The water that runs through amalgam separators comes from the suction piece at the 

chair. Most dental offices use a vacuum system. In a vacuum system, flow is not continuous and 

only occurs when the air is moving. Mr. Dube described the flow in the vacuum line as a 

“trickle”. He also added that there are some older systems in practice that are gravity fed, and do 

not use a vacuum. However, these systems are outdated and he expects that they will eventually 

all be replaced with vacuum systems. Unlike vacuum systems, gravity systems require 

continuous flow. Mr. Dube did not indicate whether any of the gravity systems have amalgam 

separators. 

Would there be a by-pass if the removal medium (filter/tank) is full or malfunctioning?

Most separator configurations have an air/water separator on the top and a solids 

collection chamber on the bottom. This configuration allows air to bypass when the collection 

chamber is full. No separation is achieved during bypass and the vacuum system will continue to 

operate. The downside of this is that, as long as everything at the chair is working, dentists may 

not be aware that the separator chamber is full and no longer functioning. However, bypass is 

important for patient safety. There is potential for significant health consequences if an amalgam 

separator shut down the vacuum while the dentist is working on a patient. 

Mr. Dube was aware of two systems from other vendors that are on the market that have 

self-contained filters, which tend to clog faster. The self-contained systems do not allow air to 

by-pass, which causes the vacuum to shut down when the separator is clogged. 

What are the allowable flow rates and capacities of your various models? What is the basis upon 

which a separator is determined to be appropriate? Anticipated flow? Anticipated amount of 

amalgam? Other?

Amalgam separators are sized based on the number of chairs at the dental practice. 

Models are designed to accommodate 1 to 4, 1 to 10, or 10 to 20 chairs. Large facilities 

consisting of more than 40 chairs include dental schools and military facilities, and some dental 

schools have up to 500 chairs. Institutional facilities of this size must have a custom designed 

amalgam separator system. 

Although models are designed for different wastewater capacities, all models are built to 

accommodate the same solids capacity (~ 1 liter (L) of solids). SolmeteX designed the collection 

cartridges to be the same for all models for shipping purposes. 
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14 January 2011 

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How are your separator efficiencies measured (ANSI, ISO, other)?

SolmeteX determines separator efficiencies using ISO 11143. Mr. Dube provided some 

clarification on the ISO 11143 Standard for amalgam separators. First, the ISO 11143 Standard is 

a particle standard based on the weight of all solids, and is not specific to mercury. Second, Mr. 

Dube stated that the ISO standard is performed in a laboratory environment and cannot be 

performed in the field due to inconsistency and unpredictable nature of dental wastewater flow 

and composition. Flow through the vacuum line occurs in trickles and only when air is flowing 

through the vacuum. Dental wastewater composition will depend on the types of operations 

being performed, which can change from minute to minute. Dental wastewater may contain a 

mixture of toothpaste, amalgam, tissue, and a wide variety of line cleaners. 

Mr. Dube also stated that amalgam separators that are tested in a laboratory are not 

necessarily tested under vacuum conditions. However, SolmeteX amalgam separators used in the 

field are always operated under a vacuum. 

The ISO 11143 Standard was updated in 2008. Mr. Dube stated that the 2008 standard is 

similar to its predecessor, and that the only major difference is the volume of water needed for 

the test. In addition, Mr. Dube acknowledged that an ANSI standard also exists; however, it does 

not differ much from the ISO standard. 

Do you have any issues with the prevalent test protocols (ANSI, ISO, Other)?

The ISO standard applies to four types of systems: 

• Type 1: Centrifuge; 

• Type 2: Sedimentation only; 

• Type 3: Filtration; and 

• Type 4: Combination of types 1, 2, and 3. 

ISO requires alarm systems for all systems, except Type 2. Type 2 systems do not require an 

alarm if they can be visually inspected; however, “visual inspection” is loosely defined in the 

standard. Mr. Dube noted that some amalgam separator models have been ISO certified based on 

a visual inspection that involved shipping the separator back to the manufacturer, and having the 

manufacturer open up the separator and check that it is working. For separators that require an 

alarm, Mr. Dube said that another amalgam separator vendor offers the alarm as an option; 

however, the alarm is located on the water container, and not the solids cartridge. As a result, the 

alarm does not perform its function of alerting the dentist when the cartridge is full. 

Where within the dental facility, are your separators usually installed? What type of wastewater 

goes through your separators?

Amalgam separators are typically located in a utility closet at the dental office and are 

installed upstream of the vacuum pump. As a result, the separator will only collect solids from 

the water from the suction piece used at the chair. Wastewater from sinks goes to a separate, 
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14 January 2011 

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gravity-fed system that is not treated by the amalgam separator. Installing the amalgam separator 

upstream of the vacuum pump is preferable because the upstream wastewater flow is much 

smaller than the wastewater flow downstream of the vacuum pump. Typical upstream flow is 

approximately one liter per day per chair. In contrast, typical flow downstream of a wet ring 

vacuum pump is approximately 360 gallons per day (over 1,350 L per day). 

Vacuum systems at dental offices include both wet and dry pumps. Wet ring vacuum 

pumps represent about 75 percent of pumps in use at dental facilities, and dry vacuum pumps 

represent the remaining 25 percent. Mr. Dube stated that wet ring pumps are more prevalent in 

the dental industry likely due to cost. Dry vacuum systems do not pull the vacuum through the 

pump and do not use water to pull a drawl. Wet ring pumps draw the vacuum through the pump 

and use water for cooling. All amalgam separator models work for both wet and dry systems 

since the separator is installed upstream of the pump. 

Mr. Dube stated that typical installation for a facility of ten chairs or less would cost 

around $250 dollars (~$1,000 for amalgam separator equipment plus installation) and only takes 

about one hour to complete. In most cases, a plumber is not necessary because the vacuum lines 

located upstream of the vacuum pump are not considered “plumbing”. Connecticut is the only 

state that requires a plumber for installation. 

Do you know of any maintenance problems identified following installation?

The most common maintenance problems result from not changing the canisters. Most 

dentists will not check the fill level on the canister on a routine basis. Because the air bypass 

allows the vacuum to continue operating even after the canister is full, dentists do not have a 

reason to check on the system. Their primary concern is keeping the dental practice running. 

SolmeteX manufactures clear amalgam separators to help promote routine visual 

inspections. In addition, Mr. Dube recommends that dentists using the SolmeteX systems change 

their cartridges every six to 12 months, or when observed full. 

It is possible for canisters to fill quickly following the initial installation due to sludge 

buildup in the vacuum line. If the lines have not been cleaned and have sludge buildup, the 

installation process can unclog the lines and immediately clog the separator. 

EPA asked why the SolmeteX models do not use an alarm to let dentists know when it is 

time to change the canisters. Mr. Dube replied that the alarm system would be a large expense, 

requiring a lot of development work, and could result in false alarms. 

Some people have raised concerns that there are limitations with existing plumbing and 

limitations on where separators can be placed. Do you have any experience with this issue?

Mr. Dube stated that these limitations would be very rare. He said that the variety of 

separator models and sizes is large enough to accommodate almost any situation. 
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On a day to day basis, what needs to be done to efficiently operate and maintain these systems? 

Who typically performs maintenance? The dentist or a third party?

Dentists need to change canisters every 6 to 12 months or when observed full. If a 

cartridge is full, then the dentist needs to contact the vendor to obtain a new cartridge. Some 

cartridges come with a recycling kit. Dentists can remove the canister themselves, use a service 

tech, or use the dealer. 

Regulatory Considerations 

Mr. Dube discussed some regulatory considerations if EPA were to select amalgam 

separators as the technology basis for the Dental Amalgam Effluent Guideline. 

Ability to Meet Discharge Limit. Mr. Dube stated that, in his opinion, amalgam separators 

would not be able to consistently meet a discharge limit. This is due to the inconsistent and 

complex chemistry of the dental wastewater. In addition, the longer that the amalgam sits in 

solution, the more it will bleed off and leach mercury. Since the separators are designed to only 

collect solid particles, dissolved mercury will not be removed. Depending on the types of 

cleaners that individual dentists use, the wastewater may contain oxidizers, which will cause the 

mercury to dissolve faster. 

EPA asked Mr. Dube if he knew how cities that have mercury limits for dentists address 

this inconsistency issue. Mr. Dube provided the city of Ontario as an example. Ontario has a 

mercury limit and requires dentists to install amalgam separators in order to obtain a license. 

However, the mercury limit is not enforced. 

Amalgam separator vendors do not guarantee performance. Mr. Dube noted that meeting 

a concentration of 1 part per billion is difficult, but not impossible since these concentrations 

have been achieved using amalgam separators on hospital wastewater. 

ISO Standards Need Clarification. Mr. Dube urged EPA to add definitions of the ISO 

standards in the text of the rule. For example, alarm locations for Type 1, 3, and 4 separators 

need to be clearly defined. Mr. Dube said that another amalgam separator vendor offers the 

alarm as an option; however, the alarm is located on the water container, and not the solids 

cartridge. As a result, the alarm does not perform its function of alerting the dentist when the 

cartridge is full. Mr. Dube stated that these situations are not being enforced because the alarm 

location specification is not prominent enough in the ISO standard text. 

Enforcement. Mr. Dube stated that dentists will not install amalgam separators if there is 

no enforcement. For example, New York City passed a regulation in May 2008. Mr. Dube 

estimates that at least 40 percent of dentists in the city have not installed amalgam separators 

because the dentists do not believe that anyone is going to inspect their facility. Mr. Dube 

recommends spot checks and an electronic system to monitor where cartridges are being sent and 

how frequently new cartridges are being purchased. 
Attachment 1 

Table A-1. List of Meeting Participants

Name Affiliation Phone Email 

Al Dube SolmeteX 508-393-5115 adube@solmetex.com 

Chrystal Beasley US EPA 202-564-0904 beasley.chrystal@epa.gov 

Tom Born US EPA 202-566-1001 born.thomas@epa.gov 

Leslie Darman US EPA 202-564-5452 darman.leslie@epa.gov 

Erik Helm US EPA 202-566-1049 helm.erik@epa.gov 

Damon Highsmith US EPA 202-566-2504 highsmith.damon@epa.gov 

Samantha Lewis US EPA 202-566-1058 lewis.samantha@epa.gov 

Jan Matuszko US EPA 202-566-1035 matuszko.jan@epa.gov 

Jan Pickrel US EPA 202-564-7904 pickrel.jan@epa.gov 

Mary Smith US EPA 202-566-1000 smith.maryt@epa.gov 

Meghan Camp ERG 703-633-1684 meghan.camp@erg.com 
Attachment 2 

SolmeteX Presentation Slides